Field of Invention
The present invention relates to a piezoelectric device provided with a piezoelectric element including a piezoelectric layer and a drive circuit to control a drive electric field applied to the piezoelectric layer, a piezoelectric actuator by using the piezoelectric device, and a hard disk drive provided with the piezoelectric actuator and an ink-jet printer apparatus.
Background Art
In recent years, instead of bulk piezoelectric materials, commercialization of a piezoelectric element by using a thin film piezoelectric material has proceeded. Examples include piezoelectric sensors taking advantage of a piezoelectric effect, in which a force applied to a piezoelectric layer is converted to a voltage, e.g., a gyro sensor, a pressure sensor, a pulse wave sensor, a shock sensor, and a microphone, piezoelectric actuators taking advantage of an inverse piezoelectric effect, in which a piezoelectric layer is deformed when a voltage is applied to the piezoelectric layer, e.g., a hard disk drive head slider and an ink-jet printer head, and a speaker, a buzzer, a resonator, and the like taking advantage of the inverse piezoelectric effect in the same manner.
Meanwhile, in the case where a piezoelectric material is made into a thin film, miniaturization of an element becomes possible, applicable fields are expanded and, in addition, mass productivity increases because many elements can be produced on a substrate in one operation. Furthermore, there are many advantages in performances, for example, the sensitivity is improved in the case where a sensor is produced.    [PTL 1] Japanese Unexamined Patent Application Publication No. 5-114760